Warning in RAM: Bolt slip class does not match slip resistance recommendations

RE: Warning in RAM: Bolt slip class does not match slip resistance recommendations

rtully14 — Mon, 14 May 2018 16:02:36 GMT

Hi Vishal. I have had the following response: 'We revised the connection in STAAD and compared to a RAM Connection Standalone model with the same data and it seems that STAAD is not working correctly with the Slip resistance check. We are looking further into this and will get back to you when we have further information. regarding your second query, internal plates are included as additional plates to the external cover plates as seen in the following figure.

These plates help the external plates in some design checks. The configuration with Internal plates alone (without the external cover plates) is not supported by the program.

RE: Warning in RAM: Bolt slip class does not match slip resistance recommendations

rtully14 — Mon, 14 May 2018 09:05:59 GMT

Hi Vishal, i am awaiting a response from the development team and will get back to one I have this ionformation.

RE: Warning in RAM: Bolt slip class does not match slip resistance recommendations

Vishal Girase — Mon, 07 May 2018 07:04:37 GMT

Hi rtully14,

Sorry for the delayed response.

Please find my comments wrt to your previous post below:

For load type Design and prevent bolt slip at ultimate combination, results are same i.e., no slip resistant check.

For load type Service and prevent bolt slip at serviceability combination, now the unity check other than slip resistant is also not shown in the result.

just for a sake of info, may i know why splices with internal plate are not included in the design,

i mean, as far as i know it differs from the external plate case in distance to calculate the net tension (plate center to center distance instead of column outer dist).

Regards,

Vishal

RE: Warning in RAM: Bolt slip class does not match slip resistance recommendations

rtully14 — Wed, 25 Apr 2018 08:40:29 GMT

Points 1 and 2

Even after selecting grades M20 HSFG (mu_0.2) warning does not disappear? Also, I don’t find any slip resistance check in the connection report?

Results for M20 Grade 8.8 bolts and M20 HSFG (mu_0.2) match irrespective of mu factor?

When the bolt with a “mu” value is selected to have the slip resistance check in the report the “Check slip resistance” flag should be checked and the combo with the “Prevent bolts slip” option should match the Load type in the loads spreadsheet. The Load types are: Design and Service. The options in the “Prevent bolts slip” combo are: Serviceability and Ultimate. For example, the data in the following figure will not add the slip resistance check in the design report because the Load type = Design and the level to prevent slip is Serviceability.

The combination in the figure above does not produce slip resistance check in the report.

Point 3

I thought if both were combined it would be easier to visualise from execution to point of view?

The way RAM Connection works is by holding one simple/shear connection in the web of members and another moment connection in the flanges. For the case of splices, a joint handles a web splice connection and a flange splice connection.

Point 4

As you note there are three options for bearing splices specified by SCI:

RAM Connection only gives option (c) above. Will option (a) and (b) be added soon?

Option (a) may be modeled using RAM Connection, providing gap equals to zero in the joint definition. Then assigning the adequate template will result in a bearing splice. However, currently we are reporting more capacities than needed as if the connection is non-bearing type. We’ll contract the report to the suggested design checks per green book design procedure.

I also noticed bearing type and non-bearing type splices provide same results (corresponding to non-bearing splices), should this be the case?

No, this is a glitch that we are fixing for next version, Bearing-type splices do not have all the checks that are currently reported. Thus, as explained in the previous point, design checks that are not required will be removed from Bearing-type report. Notice that the bearing type splice needs to be assigned to column splice joint with gap set to zero.

RE: Warning in RAM: Bolt slip class does not match slip resistance recommendations

Vishal Girase — Tue, 24 Apr 2018 03:34:20 GMT

Sorry, the template exists in the current version, only sequence is changed in the connect edition.

Don't forget to look after the points to be cleared.

RE: Warning in RAM: Bolt slip class does not match slip resistance recommendations

Vishal Girase — Wed, 18 Apr 2018 03:28:11 GMT

This seems to be CONNECT Edition, since i don't find this template in RAM connection integrated with STAAD Pro V8i 20.07.11.90.

Looking forward to your feedback for remaining points.

RE: Warning in RAM: Bolt slip class does not match slip resistance recommendations

rtully14 — Fri, 13 Apr 2018 10:09:56 GMT

Hi Vishal, regarding the difference between basic and smart connections, please see:

https://communities.bentley.com/products/ram-staad/w/structural_analysis_and_design__wiki/8105/ram-connection-capabilities-and-modeling-faq

RE: Warning in RAM: Bolt slip class does not match slip resistance recommendations

rtully14 — Fri, 13 Apr 2018 09:40:40 GMT

Hi Vishal. You can find the WAC CS template in the RAM Connection module as follows:

I will get back to you as soon as I have an answer to your other queries.

RE: Warning in RAM: Bolt slip class does not match slip resistance recommendations

Vishal Girase — Fri, 13 Apr 2018 06:49:04 GMT

Hello rtully14,

Thanks for your feedback and please see my opinion below:

For points 1 & 2:

Even after selecting grades M20 HSFG (mu_0.2), warning does not disappear,

Also I dont find any slip resistance check in the connection report as well.

What about the grade of bolt, i think it is by default 8.8?

Since results for M20 8.8 & M20 HSFG (mu_0.2) match irrespective of mu factor.

For point 3:

I thought if both were combined, it would have been easy to visualize from execution point of view.

For point 4:

I think there are 3 options provided by SCI,

External cover plate, internal cover plate and combined external & internal.

But RAM do not provide option of internal cover plate only?

If both bearing type & non bearing type splices provide same result (corresponding to non bearing splices), what is the intention of making 2 separate templates?

I was comparing it with bearing type splices design criteria.

Where i can find the WAC CS template? (code?)

Please let me know the difference in basic connections & smart connections,

since i find templates are same in both.

Thanks for your patience.

Best Regards,

Vishal

RE: Warning in RAM: Bolt slip class does not match slip resistance recommendations

rtully14 — Thu, 12 Apr 2018 09:18:10 GMT

Hi Vishal

Please see response from development team. Your queries are shown in bold and the response in italics.

I am designing a column splice of bearing type according to EN 1993-1-8. There exists net tension in the flange hence I will have to use preloaded bolts and hence apply slip resistance checks.

Now when I enable check slip resistance, I don’t find any option to enter slip factor for it. Then how does RAM cjhevck the slip resistance of the joint?

EN connection design in order to check slip resistance needs that user choose the corresponding bolt diameter. For slip resistance checks the application have bolts with different slip factor values. For example:

If user choose normal bolt diameter with “Check slip resistance” flag turned on; the application will show the design warning “Bolt slip class does not match slip resistance recommendations”.

This methodology has recently change for Indian connections, now users when turn on the “check slip resistance” flag the user is capable to set also the slip factor; but currently only available for Indian connection design.

2. Even after applying slip resistance the following warning appears in the result:

‘Bolt slip class does not match slip resistance recommendations’

What is the meaning of this warning, as far as I know only 8.8 and 10.8 grades are allowed to be used for preloaded application and IO have selected the 8.8 grade bolt, so what is the meaning of this warning?

As explained in the last questions; the warning is displayed due the user choose normal bolt diameter using the “Check slip resistance” flag turned on. Just need to choose one of the bolts using slip factor and the warning will disappear.

3. Why web and flange coverplates are checked in separate connections?

Because they are two separate connections, the web cover plate is one and the flange cover plate is the other. In other codes not only a plate could be user to join the webs but also double angles, etc. That is the reason of why we separate shear and moment connections so we can combine them if required.

4. What is the purpose of providing additional plate from inside of column, as far as I know SCI allows use of cover plate either from inside or outside.

I am using RAM Connection integrated with STAAD.Pro V8i 20.07.11.90.

Green book describes the use for internal cover plates. The EN connection design follow the procedures described in:

The consideration or not of the internal cover plates affect directly to bending capacities in major and minor axis; also affecting in plate shear capacity.

If user turn on the flag the interior plate will be considered in the capacities.

Also, in the results:

In above it refers to SCI P358 p 185 however, that page refers to non-bearing splices and NOT bearing splices:

The references in the report results are correct. The user is reporting the flange cover plate from a Non-bearing connection design.

The only template that user can assign to have a bearing type connection is the “Smart WAC CS”; which use a division plate between columns. Also is noticed that the model is using standard bolts with the check slip resistance flag turned on. Once the user change to the correct one the warning will disappear.

Should the refereance be to SCI P358 p 176?

The only template exclusively for Bearing Type is WAC CS (Web angle cleats – Column splice) which uses the division plate between the columns. If user model use the correct template (bearing type) the reference should be the one described above.

RE: Warning in RAM: Bolt slip class does not match slip resistance recommendations

rtully14 — Wed, 11 Apr 2018 07:49:30 GMT

Hi Vishal, I noticed that the refereance to page 185 was for non-bearing splices and queried this with the development team. The page number should be 176 for bearing splices. With reference to your query (3) i think this is simply due to the SCI publication giving design recommendations for the web and flange seperately. I will look into the results for bearing and non bearing splices.

RE: Warning in RAM: Bolt slip class does not match slip resistance recommendations

Vishal Girase — Wed, 11 Apr 2018 07:30:42 GMT

One more point, I noticed that

Results for bearing & non-bearing splices are same!!!!!

Please ensure at your end.

It is for non bearing type of splices irrespective of selection (I haven't checked all the formulas, only could check few initial points as well as reference is given as SCI 358 p185, which is for Non-bearing splices).

Let me know whether you also notice the same.

Regards,

Vishal

RE: Warning in RAM: Bolt slip class does not match slip resistance recommendations

Vishal Girase — Wed, 11 Apr 2018 07:10:32 GMT

Hello rtully,

Please don't be.

RE: Warning in RAM: Bolt slip class does not match slip resistance recommendations

rtully14 — Tue, 10 Apr 2018 15:30:00 GMT

Hi Vishal. I am looking for clarification of a few points from the development team and will respond to you after I recieve these.

RE: Warning in RAM: Bolt slip class does not match slip resistance recommendations

rtully14 — Tue, 10 Apr 2018 07:19:34 GMT

Hi Vishal, my apologies for the delay, yes I am looking into your query and will get back to you later today with my findings.

RE: Warning in RAM: Bolt slip class does not match slip resistance recommendations

Vishal Girase — Tue, 10 Apr 2018 03:22:58 GMT

Hello,

May I know whether any one is looking into the problem or not?

Or Isn't my question valid?

Please let me know.

RE: Warning in RAM: Bolt slip class does not match slip resistance recommendations

Vishal Girase — Fri, 06 Apr 2018 03:50:27 GMT

Hello Bentley,

Any comments?

RE: Warning in RAM: Bolt slip class does not match slip resistance recommendations

Vishal Girase — Tue, 03 Apr 2018 14:11:25 GMT

Hello,

I have uploaded the file via secure file upload path.

There is only one connection defined in the file at node no. 176.

1) I have found under connector that bolt class like

M12 G8_8

and so on, also bolt like

M12 HSFG (mu_0.2)

This means high strength friction grip, friction factor 0.2, am I right?

but where is the grade?

Also i don't find slip resistance check in the results.

RE: Warning in RAM: Bolt slip class does not match slip resistance recommendations

rtully14 — Tue, 03 Apr 2018 13:12:33 GMT

Hi Vishal can you please attach your STAAD.Pro file and confirm the node where the column splice has been specified?